This invention relates to refrigeration systems, and in particular, to a refrigeration system wherein the arrangement of the valves used for temperature and humidity cooling are simplified.
Refrigeration systems are used to control the temperature and humidity in user selected environments such as test chambers. As is conventional, the refrigeration system includes evaporator coils positioned within (or adjacent) a chamber wherein the environment is to be controlled. Refrigerant is supplied to the evaporator coils by a conventional compressor/condenser system. The compressor receives refrigerant in a gaseous form from the evaporator coils and compresses the refrigerant. The heat of compression is removed by the condenser and the refrigerant is provided in liquid form to two distinct expansion valves, namely, a temperature-cooling expansion valve and a humidity-cooling expansion valve. The flow of refrigerant to the expansion valves is controlled by corresponding liquid solenoid valves. During temperature cooling, a user selects a desired temperature within the chamber and the flow of refrigerant is modulated by the liquid solenoid valve and by the temperature-cooling expansion valve in order to maintain the chamber at a user desired level. During humidity-cooling, a user selects a set point and the flow of refrigerant is modulated by the other liquid solenoid valve and by the humidity-cooling expansion valve in order to optimize the dry bulb temperature and predetermined humidity within the chamber. While functional for its intended purpose, this prior art arrangement is complex and requires additional amounts of labor to pipe and wire the necessary components.
Therefore, it is a primary object and feature of the present invention to provide a refrigeration system wherein the arrangement of the valves used for temperature and humidity cooling is simplified.
It is a further object and feature of the present invention to provide a refrigeration system with fewer components and greater reliability than prior art systems.
It is still a further object and feature of the present invention to provide a refrigeration system which is simple and inexpensive to construct.
It is a still further object and feature of the present invention to provide a refrigeration system which utilizes a single expansion valve for use in both temperature and humidity cooling.
In accordance with the present invention, a refrigeration system is provided having refrigerant flowing therethrough. The refrigeration system provides temperature and humidity cooling within a chamber. The refrigeration system includes a compressor having an input and an output. An evaporator coil is in communication with the chamber. The evaporator coil has an input operatively connected to the output of the compressor by an input line and an output operatively connected to the input of the compressor by an output line so as to allow the refrigerant to circulate between the compressor and the evaporator coil. An expansion valve is provided in the input line for controlling the flow rate of refrigerant delivered to the evaporator coil and for limiting the pressure of refrigerant delivered to the input of the compressor.
A liquid solenoid valve may be provided in the input line upstream of the expansion valve. The input solenoid valve controls the flow of refrigerant to the expansion valve. A pressure regulating valve is positioned in the output line. The pressure regulating valve maintains a minimum temperature of refrigerant within the evaporator coils so as to prevent moisture from freezing on the evaporator coil during humidity cooling. A suction solenoid valve is connected in parallel across the pressure regulating valve. The suction solenoid valve is movable between a first closed position wherein a refrigerant flows through the pressure regulating valve and a second opened position wherein the flow refrigerant bypasses the pressure regulating valve.
A sensing structure is operatively connected to the expansion valve and positioned adjacent the output line downstream of the pressure regulating valve. The sensing structure provides a signal to the expansion valve. The signal is provided by the sensing structure to the expansion valve and corresponds to the temperature of the refrigerant flowing through the output line and/or the pressure of the refrigerant flowing through the output line. The sensing structure may include a sensing bulb and/or an equalizer line.
In accordance with a still further aspect of the present invention, a refrigeration system is provided having refrigerant flowing therethrough. The refrigeration system provides temperature and humidity cooling within a chamber. The refrigeration system includes a compressor having an input and an output. An evaporator coil is in communication with the chamber. The evaporator coil has an input operatively connected to the compressor by an input line and output operatively connected to the input of the compressor by an output line so as to allow the refrigerant to circulate between the compressor and the evaporator coil. A pressure regulating signal is provided in the output line for maintaining a minimum temperature of refrigerant within the evaporator coils so as to prevent moisture from freezing in the evaporator during humidity cooling. A suction solenoid valve is connected in parallel with the pressure regulating valve. The suction solenoid valve is movable between a first closed position to prevent the flow of refrigerant therethrough and a second opened position allowing the flow of refrigerant therethrough.
A sensing structure may be operatively connected to the expansion valve in a position adjacent the output line downstream of the pressure regulating valve. The sensing structure provides at least one signal to the expansion valve. The expansion valve varies the flow rate of the refrigerant delivered to the input of the evaporator coil in response to the at least one signal received from the sensing structure. The sensing structure may include a sensing bulb for providing a temperature signal to the expansion valve which corresponds to the temperature of the refrigerant flowing through the output line. The sensing structure may also include an equalizer line for providing a pressure signal to the expansion valve which corresponds to the pressure of the refrigerant flowing through the output line. It is contemplated that the pressure of the refrigerant delivered to the input of the evaporator coil be sufficient to prevent moisture from freezing on the evaporator coil during humidity cooling.
In accordance with a still further aspect of the present invention, a refrigeration system is provided having refrigerant flowing therethrough. The refrigerant system provides temperature and humidity cooling within a chamber and includes a compressor having an input and an output. An evaporator coil is in communication with the chamber. The evaporator coil has an input operatively connected to the compressor by an input line and output operatively connected to the input of the compressor by an output line so as to allow the refrigerant to circulate between the compressor and the evaporator coil. An expansion valve is provided in the input line for varying the flow rate of refrigerant delivered to the input of the evaporator coil. A pressure regulating valve is positioned in the output line. The pressure regulating valve maintains a minimum temperature of refrigerant within the evaporator coil. A suction solenoid valve connected in parallel to the pressure regulating valve is movable between a first closed position for preventing the flow of refrigerant therethrough and a second opened position for allowing the refrigerant therethrough. A second bulb is operatively connected to the expansion valve. The sensing valve provides a temperature signal to the expansion valve which corresponds to the temperature of the refrigerant flowing through the output line. An equalizer line is operatively connected to the expansion valve. The equalizer line provides a pressure signal to the expansion valve which corresponds to the pressure of the refrigerant flowing through the output line. It is contemplated that the expansion valve varies the flow rate of refrigerant delivered to the input of the evaporator coil in response to the temperature signal.
A condenser may be positioned in the input line to remove heat from the refrigerant exiting from the compressor. A liquid solenoid valve is also provided in the input line and upstream of the expansion line. The liquid solenoid valve controls the flow of refrigerant to the expansion valve. The pressure of the refrigerant delivered to the input of the evaporator coil is sufficient to prevent moisture from freezing on the evaporator coil during humidity cooling.